Refrigerant systems in vehicles generally include a refrigerant compressor lubrication system of the passive type with swash or wobble plate drive mechanisms using oil entrained in the refrigerant to lubricate the mechanisms critical bearing surfaces. An example of a refrigerant compressor lubrication system is disclosed in the U.S. Pat. No. 4,480,964 to Skinner, issued Nov. 6, 1984 and assigned to the assignee of the present invention. The assembly is of the type connected in an automotive air conditioning system having a normal condenser, orifice tube, evaporator, and an accumulator arranged in that order between the compressor's discharge and suction sides. Generally, the compressor includes a cylinder block having a head and a crank case sealingly clamped to opposite ends thereof. A drive shaft is supported centrally in the compressor at the cylinder block and crank case. The drive shaft extends through the crank case for connection to an automotive engine. The cylinder block includes a plurality of axial cylinders, a piston rod connecting a piston to a nonrotary ring shaped wobble plate received about the drive shaft through each of the cylinders. The end of each piston rod is connected to the wobble plate by a spherical rod end which is retained in a socket on the wobble plate by a split retainer ring which has a snap fit with the wobble plate. During operation of the assembly, reciprocation of the piston rods places stresses in the axial direction directly on the retainer rings. It is desirable to provide for the operation of the variable displacement compressor at higher RPM, however, there are inherent limitations on the stresses that can be placed on the retainer ring.
The U.S. Pat. No. 4,548,254 to Roberts, issued Oct. 22, 1985 discloses a method of manufacturing a swash plate assembly for use in a compressor. A plurality of ball ended rods have a pair of split die inserts positioned about the rod, each against one of the balls. The balls are positioned in a die having a central core to locate their position and which die securely maintains the inserts against each of the ball ends. A piston is cast about one ball end of the rod and the opposite ball end, which is positioned in a mating swash plate socket, has a swash plate cast about it. Tolerances for maximized performance are very difficult to obtain when casting about a ball end.
The present invention provides a socket plate, commonly referred to as wobble or swash plate, for allowing the operation of a variable stroke, variable displacement compressor at higher RPM.